A driver or a passenger of a vehicle typically operates various devices in the vehicle using switches, screens, keypads or other input mechanism using fingers or hands. Such input mechanisms may be used to operate, for example, a navigation system, an entertainment system, a climate system or a phone system. Sometimes, a complicated series of operations must be performed on the input mechanism to issue a desired command to the devices. However, it is preferable for the driver to keep both hands on a steering wheel and operate these input devices by a hand intermittently for only a brief period of time. Depending on the complexity of the operations, it may take multiple attempts to operate the input devices before the driver can perform operations as desired.
Hence, it is advantageous to use a mode of operation that makes less use of a driver's hands. One mode of such operation is speech recognition. Speech recognition is the process of converting an acoustic signal to speech elements (e.g., phonemes, words and sentences). Speech recognition has found application in various areas ranging from telephony to vehicle operation. In a speech recognition system, the audio signal is collected by input devices (e.g., a microphone), converted to a digital signal, and then processed using one or more algorithms to output speech elements contained in the audio signal. Depending on the field of application, the recognized speech elements can be the final results of speech recognition or intermediate information used for further processing.
One of the issues in using voice recognition in vehicles is that similar or the same verbal commands may be used for different devices. Sharing of similar or the same verbal commands causes ambiguity in verbal commands. For example, a command such as “locate XYZ” may indicate the locating of a particular point-of-interest (POI) in the context of navigation whereas the same command may also indicate identification of a sound track in an entertainment system. If the context of the user's command is not properly identified, operations other that what are intended by the user may be carried out by the devices in the vehicle.
Unintended operations and time spent in subsequent remedial actions due to ambiguous verbal command may deteriorate user experience and cause the user to revert to manual operations.